Avaliação da qualidade da água do reservatório de Nossa Senhora das Dores - SE através do índice de qualidade da água de reservatório - IQAR

Abstract

This study aimed to evaluate the seasonal quality of the water from the Public Water Reservoir located in the municipality of Nossa Senhora das Dores - Sergipe. This reservoir belongs to the sub-basin of the Siriri River, located in the coordinates 10 ° 29'31,32 ''S - 37 ° 11'11,83''O. The monitoring activities were performed in the period between 2014 and 2016. The water samples were collected in the dry and rainy periods and water temperature and depth of sampling were measured in situ. The samples were stored in 3 aliquots, refrigerated and taken to the laboratory for analysis of pH, Turbidity (Turb), Dissolved Oxygen (DO), Dissolved Organic Carbon (DOC), chlorophyll a (Chlo-a) Coliform Thermotolerant (CT), Total Phosphorus, Total Nitrogen, Ammonia (NH3), Nitrate (NO3 - ), Electrical Conductivity (EC) and Total Dissolved Solids (TDS). Regarding the comparison with current legislation, CONAMA Regulation 357/05, the variables Turbidity, Chlorophyll and Total phosphorus belong to Class 4; According to the observed values for thermotolerant coliforms and dissolved oxygen, the water from the reservoir is unfit for use and belongs to Class 3; The values for pH, Nitrate and Total Dissolved Solids classify the reservoir as class 2, and Ammonia, as class 1. The electrical conductivity is above the limits established by CETESB. The Reservoir Water Quality Index (RWQI) indicates Class IV- critically degraded and polluted, for both dry and rainy periods. It is attributed to Total Nitrogen and Chlorophyll the contribution to the poor RWQI result. Regarding the statistical analysis, the Pearson Correlation Matrix was significant among the parameters EC, TDS, P, Chlo-a and T. Through the analyzes, it was possible to observe evidence that the reservoir is eutrophic and out of the current legislation standards.